Python
Python Basics
1. Introduction to Python
Python is an interpreted, high-level, dynamically typed programming
language.
It supports multiple programming paradigms: procedural, object-oriented, and
functional.
Python uses indentation for code blocks instead of {} .
2. Python Syntax
Comments: # This is a comment
Multi-line comments: """ This is a multi-line comment """
Variables: No need to declare types.
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x = 10 # Integer
y = 3.14 # Float
name = "Python" # String
is_active = True # Boolean
3. Data Types
Numeric: int , float , complex
Text: str
Boolean: True , False
Sequence: list , tuple , range
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Set: set , frozenset
Mapping: dict
Binary: bytes , bytearray , memoryview
4. Operators
Arithmetic: + , , , / , // , % , *
Comparison: == , != , > , < , >= , <=
Logical: and , or , not
Assignment: = , += , = , = , /=
Membership: in , not in
Identity: is , is not
Control Flow
1. Conditional Statements
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if condition:
# code block
elif condition:
# code block
else:
# code block
2. Loops
For Loop
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for i in range(5): # 0 to 4
print(i)
While Loop
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x=0
while x < 5:
print(x)
x += 1
Loop Control Statements
break : Exits the loop
continue : Skips the current iteration
pass : Placeholder for empty loops
Functions
1. Defining Functions
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def greet(name):
return f"Hello, {name}!"
2. Default Arguments
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def greet(name="User"):
return f"Hello, {name}!"
3. Lambda Functions
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add = lambda x, y: x + y
print(add(5, 3)) # Output: 8
Data Structures
1. Lists (Mutable)
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fruits = ["apple", "banana", "cherry"]
fruits.append("mango") # Add item
fruits.remove("banana") # Remove item
fruits[0] = "grape" # Modify item
2. Tuples (Immutable)
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coordinates = (4, 5)
3. Dictionaries
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person = {"name": "Alice", "age": 25}
print(person["name"]) # Alice
person["city"] = "New York" # Add key-value pair
4. Sets (Unique Values)
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numbers = {1, 2, 3, 4}
numbers.add(5)
Object-Oriented Programming (OOP)
1. Class & Objects
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class Car:
def __init__(self, brand, model):
self.brand = brand
self.model = model
def display(self):
print(f"Car: {self.brand} {self.model}")
car1 = Car("Toyota", "Corolla")
car1.display()
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2. Inheritance
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class ElectricCar(Car):
def __init__(self, brand, model, battery):
super().__init__(brand, model)
self.battery = battery
File Handling
1. Read File
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with open("file.txt", "r") as file:
content = file.read()
2. Write File
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with open("file.txt", "w") as file:
file.write("Hello, World!")
Modules & Libraries
1. Importing Modules
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import math
print(math.sqrt(16)) # 4.0
2. Creating Modules
Create mymodule.py :
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def greet(name):
return f"Hello, {name}!"
Use it in another file:
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import mymodule
print(mymodule.greet("Alice"))
Exception Handling
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try:
x = 10 / 0
except ZeroDivisionError:
print("Cannot divide by zero!")
finally:
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print("Execution finished.")
Python Advanced Topics
1. List Comprehension
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squares = [x**2 for x in range(10)]
2. Decorators
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def decorator(func):
def wrapper():
print("Before function call")
func()
print("After function call")
return wrapper
@decorator
def say_hello():
print("Hello!")
say_hello()
3. Multithreading
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import threading
def print_numbers():
for i in range(5):
print(i)
t = threading.Thread(target=print_numbers)
t.start()
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